This is a continuation-in-part of U.S. patent application Ser. No. 220,654, filed Dec. 29, 1980.
This invention relates generally to lubricants and more particularly has reference to lubricants containing a dispersion of solid lubricant particles, a vapor degreasing agent and a corrosion inhibitor and a carrier, vehicle or solvent.
Pertinent United States and foreign patents are found in Class 252, subclasses 60 and 58 and in Class 585, subclass 12 of the Official Classification of Patents in the United States Patent and Trademark Office.
Examples of pertinent patents are U.S. Pat. Nos:
______________________________________ 2,510,112 3,159,557 3,194,762 3,314,889 3,432,431 3,493,513 3,505,229 3,536,624 3,640,859 3,723,317 3,933,656 4,029,870 4,127,491 4,224,173. ______________________________________
U.S. Pat. No. 4,224,173 describes an eight step method for making lubricant oil containing polytetrafluoroethylene particles and a fluorochemical surfactant.
U.S. Pat. No. 2,510,112 describes an aqueous dispersion of colloidal polymerized polytetrafluoroethylene in a fluorinated hydrocarbon oil.
U.S. Pat. No. 3,194,762 describes a product having resin particles suspended in an oil base.
U.S. Pat. Nos. 3,159,557; 3,432,431; 3,493,513; 3,505,229; 3,630,901 and 3,640,859 describe greases containing polytetrafluoroethylene particles.
U.S. Pat. No. 3,723,317 describes a grease wherein triazene is combined with polytetrafluoroethylene to thicken a fluorinated polyether base oil.
U.S. Pat. No. 4,029,870 describes unsintered polytetrafluoroethylene which has been irradiated.
U.S. Pat. No. 3,933,656 describes sub-micron polytetrafluoroethylene particles.
U.S. Pat. No. 4,127,491 describes an aqueous dispersion of polytetrafluoroethylene particles.
The benefits of solid particle lubricant additives have been recognized for some time. Tests indicate varying but consistent improvements in engine efficiency through the use of molybdenum disulfide and graphite. The effects of solid particles as a cushion between sliding metal parts having been established, the natural tendency is to develop improved or advanced products. Polytetrafluoroethylene has been introduced as a solid particle additive that exhibits the same cushioning effects as molybdenum disulfide and graphite, but with the advantage of being a cleaner material to work with and a better or lower friction lubricant.
However, there are several problems associated with the use of polytetrafluoroethylene particle additives.
The preparation of a stable dispersion through chemical stabilization of polytetrafluorethylene is a complex and exacting science. One such stabilization technique is described in U.S. Pat. No. 4,127,491.
Moreover, the dispersion achieved by the chemical stabilization method is short-lived. Upon standing for short periods of time, the particles settle and develop what could be called a "hard settle", i.e., the particles cannot be redispersed.
Added to the "hard settling" problem are the in-service problems of short-lived effectiveness. The apparent problem with dispersions achieved by the chemical stabilization method is that the surface active materials and film forming polymers become ineffective after a brief period of use.
Conventional liquid lubricants are, for the most part, single purpose. That is they usually are directed to performing a single task such as reducing friction of contacting parts by covering the parts with a thin film. It is well known that conventional lubricants contain additives for one or more special purposes in addition to the basic objective of lubrication. Such additives may deter environmentally created surface degradation such as oxidation and corrosion; extend the life of surfaces which are constantly exposed to ultraviolet radiation; deter build-up in/or facilitate easy removal of debris (e.g., dust, dirt, salt, marine growth); prevent or reduce moisture penetration of protective materials which can lead to corrosion and failure of the protected object or assembly; and more rarely, reduce fluid friction drag. Usually the lubricant additive is targeted towards protecting that which is being lubricated from one or two different situations. The present invention provides a specialized lubicant in addition to a broad scope protective additive.